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<!DOCTYPE html> |
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<meta charset="utf-8"> |
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<style> |
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.axis { |
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font: 10px sans-serif; |
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} |
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.axis path, |
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.axis line { |
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fill: none; |
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stroke: #000; |
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shape-rendering: crispEdges; |
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} |
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.axis--y path { |
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display: none; |
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} |
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.line path { |
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fill: none; |
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stroke-width: 1.5px; |
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stroke-linejoin: round; |
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} |
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.line text { |
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font: bold 12px sans-serif; |
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text-shadow: 1px 1px 0 #fff, -1px -1px 0 #fff, 1px -1px 0 #fff, -1px 1px 0 #fff; |
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} |
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</style> |
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<body> |
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<script src="//d3js.org/d3.v4.0.0-alpha.29.min.js"></script> |
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<script> |
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var data = [ |
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{name: "HSL Rainbow", labelOffset: 60, value: function(t) { return d3.hsl(t, 1, 0.5); }}, |
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{name: "HCL Rainbow", labelOffset: 20, value: function(t) { return d3.hcl(t, 1, 0.5); }}, |
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{name: "Cubehelix Rainbow", labelOffset: 40, value: d3.scaleRainbow().domain([0, 360])} |
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].map(function(color) { |
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return color.deltas = d3.range(0, 360, 3).map(function(x) { |
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return { |
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input: x, |
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delta: delta(color.value(x - 10), color.value(x + 10)) |
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}; |
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}), color; |
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}); |
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var margin = {top: 20, right: 20, bottom: 30, left: 30}, |
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width = 960 - margin.left - margin.right, |
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height = 500 - margin.top - margin.bottom; |
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var x = d3.scaleLinear() |
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.domain([0, 360]) |
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.range([0, width]); |
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var y = d3.scaleLinear() |
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.domain([0, 80]) |
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.range([height, 0]); |
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var z = d3.scaleCategory10(); |
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var line = d3.line() |
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.curve(d3.curveBasis) |
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.x(function(d) { return x(d.input); }) |
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.y(function(d) { return y(d.delta); }); |
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var svg = d3.select("body").append("svg") |
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.attr("width", width + margin.left + margin.right) |
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.attr("height", height + margin.top + margin.bottom) |
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.append("g") |
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.attr("transform", "translate(" + margin.left + "," + margin.top + ")"); |
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svg.append("g") |
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.attr("class", "axis axis--x") |
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.attr("transform", "translate(0," + y(0) + ")") |
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.call(d3.axisBottom(x)); |
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svg.append("g") |
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.attr("class", "axis axis--y") |
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.call(d3.axisLeft(y)) |
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.selectAll(".tick:last-of-type") |
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.append("text") |
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.attr("class", "axis-title") |
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.attr("x", 3) |
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.attr("dy", ".32em") |
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.text("Color Difference at ±10° (CIE76)"); |
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var g = svg.selectAll(".line") |
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.data(data) |
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.enter().append("g") |
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.attr("class", "line"); |
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g.append("path") |
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.attr("d", function(d) { return line(d.deltas); }) |
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.attr("id", function(d, i) { return "path-" + i; }) |
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.style("stroke", function(d, i) { return z(i); }); |
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g.append("text") |
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.attr("x", function(d) { return d.labelOffset; }) |
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.attr("dy", -5) |
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.style("fill", function(d, i) { return d3.lab(z(i)).darker(); }) |
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.append("textPath") |
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.attr("class", "textpath") |
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.attr("xlink:href", function(d, i) { return "#path-" + i; }) |
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.text(function(d) { return d.name; }); |
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// CIE76 per https://en.wikipedia.org/wiki/Color_difference#CIE76 |
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// Not as good as CIEDE2000 but a lot easier to implement. |
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function delta(a, b) { |
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var dl = (a = d3.lab(a)).l - (b = d3.lab(b)).l, da = a.a - b.a, db = a.b - b.b; |
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return Math.sqrt(dl * dl + da * da + db * db); |
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} |
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</script> |